1ynf
From Proteopedia
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'''Crystal Structure of N-Succinylarginine Dihydrolase, AstB, bound to Substrate and Product, an Enzyme from the Arginine Catabolic Pathway of Escherichia coli''' | '''Crystal Structure of N-Succinylarginine Dihydrolase, AstB, bound to Substrate and Product, an Enzyme from the Arginine Catabolic Pathway of Escherichia coli''' | ||
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[[Category: Schrag, J D.]] | [[Category: Schrag, J D.]] | ||
[[Category: Tocilj, A.]] | [[Category: Tocilj, A.]] | ||
| - | [[Category: | + | [[Category: Dihydrolase]] |
| - | [[Category: | + | [[Category: Succinylarginine]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 16:32:35 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 13:32, 3 May 2008
Crystal Structure of N-Succinylarginine Dihydrolase, AstB, bound to Substrate and Product, an Enzyme from the Arginine Catabolic Pathway of Escherichia coli
Overview
The ammonia-producing arginine succinyltransferase pathway is the major pathway in Escherichia coli and related bacteria for arginine catabolism as a sole nitrogen source. This pathway consists of five steps, each catalyzed by a distinct enzyme. Here we report the crystal structure of N-succinylarginine dihydrolase AstB, the second enzyme of the arginine succinyltransferase pathway, providing the first structural insight into enzymes from this pathway. The enzyme exhibits a pseudo 5-fold symmetric alpha/beta propeller fold of circularly arranged betabetaalphabeta modules enclosing the active site. The crystal structure indicates clearly that this enzyme belongs to the amidinotransferase (AT) superfamily and that the active site contains a Cys-His-Glu triad characteristic of the AT superfamily. Structures of the complexes of AstB with the reaction product and a C365S mutant with bound the N-succinylarginine substrate suggest a catalytic mechanism that consists of two cycles of hydrolysis and ammonia release, with each cycle utilizing a mechanism similar to that proposed for arginine deiminases. Like other members of the AT superfamily of enzymes, AstB possesses a flexible loop that is disordered in the absence of substrate and assumes an ordered conformation upon substrate binding, shielding the ligand from the bulk solvent, thereby controlling substrate access and product release.
About this Structure
1YNF is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of N-succinylarginine dihydrolase AstB, bound to substrate and product, an enzyme from the arginine catabolic pathway of Escherichia coli., Tocilj A, Schrag JD, Li Y, Schneider BL, Reitzer L, Matte A, Cygler M, J Biol Chem. 2005 Apr 22;280(16):15800-8. Epub 2005 Feb 9. PMID:15703173 Page seeded by OCA on Sat May 3 16:32:35 2008
